PREFIX_SIZE
offset = jj + PREFIX_SIZE;
size = vc->pkt_size - PREFIX_SIZE;
usbInSize = outImageSize + PREFIX_SIZE; /* always send prefix */
if (PREFIX_SIZE - wrote > 0)
return PREFIX_SIZE - wrote;
if (pos >= PREFIX_SIZE)
buf[PREFIX_SIZE - 1] = '\0';
char buf[PREFIX_SIZE] = "";
char buf[PREFIX_SIZE] = "";
char buf[PREFIX_SIZE] = "";
char buf[PREFIX_SIZE] = "";